This invention relates to a tubing applicator for placing tubing sections onto wire leads, and more specifically to an apparatus which shears tubing sections from a continuous reel, shapes the tubing, and precisely positions it onto the terminated end of a wire lead which is carried by a conveyor.
The use of heat shrinkable tubing to protect electrical connections is well known. Shrink tubing is a plastic material which is expanded under controlled conditions and shrinks back to its original shape when exposed to heat. Thus tubing slightly larger than the connection to be encapsulated is placed thereon, then exposed to heat to shrink the tubing around the connection and adjacent portions of wire to insulate the connection. While insulating connections has been found to be desirable, as a hand procedure it is quite time consuming and adds considerably to the labor costs of products having shrink tubing insulation. Further, repeated precise placement of tubing sections on connections is difficult as a manual task.
U.S. Pat. No. 3,812,568 discloses an apparatus which delivers pieces of precut shrink tubing to a waiting position adjacent an operator where a lead is inserted and a lateral conveyor picks up the assembly and transports it to a heater for shrinking. The tubing section is transported to the waiting position between conveyors driven in opposite directions which converge to compress the section into an oval shape for snug fit onto a flat connector. The assembly then passes an adjustable stop parallel to the conveyor which positions the section relative to the terminal to establish the desired alignment between the tubing section and the connector prior to heating.
U.S. Pat. No. 4,239,485 discloses an apparatus which delivers sections of shrink tubing supplied on a tape to a control station for insertion of a terminal. A conductor is positioned through the sleeve then gripped by jaws which carry it through a hot air heater for shrinking.